Knife-drive for cloth-cutting machines.



H. NIAIIVIIN 6L W. I. MARSHALL.

KNIFE DRIVE FOR CLOTH CUTTING MACHINES.

APPLICATION FILD NON. I7. I9I7.

Patented Jan. 28, 1919.

UNITED sTATEs rATENT oFIIcE.

HYMAN MAIMIN, OF'NEW YORK, N. Y., AND WILLIAM J. MARSHALL, OF NEWARK,NEW JERSEY, ASSIGNORS TO H. MAIMIN CO., INC., A CORPORATION OF NEW YORK.

KNIFE-DRIVE FOR CLOTH-CUTTING MACHINES.

Specification of Letters Patent.

Patented Jan. '28, 1919.

Application filed November 17, 1917. Serial N o. 202,562.

To all 'whom t may concern Be it known that we, I-IYMAN MAIMIN andWILLIAM J. MARSHALL, both citizens of the United States, said MAIMINresiding in the city, county, and State of New York, and said MARSHALLresiding in Newark, county of Essex, and State of New Jersey, 'haveinvented. certain new and useful Improvements in Knife- Drives forCloth- Cutting Machines; and we do hereby declare the following to be afull,clear, and exact-v description of the invention," such as willenable others skilled in the art to which it appertains to make and usethe same.

The invention relates to improvements in cloth cutting machines of thattype in which a vertically reciprocating cutting knife is` driven byarotary motor, a's,for example, an electric motor having a. rotatingarmature.

In machines of this type, as rnow commonly employed, the knife is drivenat very high speeds in order that the cutting operation Imay proceedrapidly and4 effectively. These speeds run as high as three thousandrevolutions per minute of the Aarmature shaft, and this shaft isdirectly connected to the knife toproduce three thousand complete up anddown strokes per minute. The knife is made as thin as is consistent withgood cutting and a portion of the blade is incasedin a knife sheath orslot within the uprising standard of the cloth cutting machine. Inasmuchas the resistance to the forward'movement of the knife through the cutcloth increases with any increase in thickness of theknife and of theincasing standard,'it is highly important that the knife should be thinand that the sheath should fit it closely. On the other hand, if, foranyreason, lthe blade ofthe knife comes into contact with the wall oftheSheath, the high speed will immediately give rise to a destructiveheating and wearing of the knife blade. It has been the common racticeto fasten the knife in the lower end of a vertically reciprocatingholder, which holder is driven from the rotating motor' through a vcrankand pitman, and the pitman hasusually been connected at its lower end`either directly tothe knife holder or to "a suitably guided crossheadattached to the upper end of the knife'- tical guiding surface. Whenthese machines are in use the down stroke is of the nature of aIchopping stroke in that the lower or horizontal cutting edge of thelmife is forced downwardly through the cloth. In other Words, thedriving pitrnan is required to impart a violent thrust or blow to thedriven knife holder just at the beginning of the downward stroke, and ithas been found in ractice that this has resulted in marked ocalized wearof the vertical guideways. As soon as this wear becomes evident, itresults 1n a certain amount of play at that part of the guideways and isaccompanied by a violent vibration o-f the entire cutting machine,

so that the accuracy of the cutting is interfered with and the wearrapidly progresses .to a point where the machine has to be repaired.

It is the object of the present invention to overcome these difficultiesby providing a so guided, and may have the driving force so applied toit, that the knife will not contact with the wall of the sheath and thewear and tendency toward lateral movement, due to the above describedthrust, is done away with. -To that end, we have adopted the mechanicalconstruction and arrangement illustrated in the drawings and hereinafterdescribed. The foregoing remarks, togethery with the description of thespecific embodiment shown, will make clear the principles of theinvention, and it will be understood that the mechanical elementsdescribed may take many equivalent forms without departin from thespirit of the invention.

n the drawings, Figure l is a front view of a cloth cutting machineequipped with the knife-driving mechanism of our invention, the frontplate of the machine being removed; Fig. 2 is a side elevation partlybroken away to disclose the driving mechanism, and Fig. 3 is a plan viewof the front portion of the machine likewise broken away to disclose thedriving mechanism.

The machine has the usual foot plate 1 and standard 2 which supports thedriving vmotor 3 and is provided with an operating handle 4. As iscustomary, the rear portion of the knife blade 5 is closely embraced bya groove or sheath in the standard 2, as shown in dotted lines in Fig.2, and the knife and sheathing standard are made` as narrow` as isconsistent with good cutting and yrigidity, for the purpose above"described.

In accordance with our invention there is connected to the upper end ofthe knife a driving -rod 6 which should be of ample 'strengthandrigidity as shown. This rod is rigidly secured at its upper end toatcrosshead 7 which is provided with a transverse slot or groove 8 toreceive a crankpin 9 extending from a crank 'or crank fdisk L10 securedto the end of the shaft of the' electric motor 8. It will be observedthat the construction and arrangement of this cro-sshe'ad is such thatonly the downward thrust of the crank pin, and not the lateral thrust,is imparted to the crosshead. The crosshead 7 is guided in its verticalmovement by suitable guides which are here shown in the form of a pairof vertically extending rods or pillars l1 embraced by integral Wingportions l2 of the crosshead.

kblock 13 containing a centrally located bore through which the rod 6.passes and in which it closely fits. This block may be as long as isfound necessary "to accurately guide-the rod 6 so as to ventirely insurethe perfectly true ruiming ofthe knife within its sheath.

- `ln'thev construction shown, the bars or lpill lars 1l lare anchoredfat their lower ends in this block, but it will `be understood that ifypreferred kthese bars or pillars 1l lmay ybe anchored in the permanentframe of the machine itself.

It willyhowever, be observed that inthe preferred construction hereillustrated `the bars or .pillars 11 lare positioned infront of and onopposite sides ofthe bore through the `guide block '13, lso that linesjoiningi'the vcenters of these three guiding elements form a triangle.This construction is adopted for the purpose of aording great vrigidityyof the guiding means against any thrust tending to move the yknife backand forth in its own plane and it supplements the above described meansof preventing lateral vibracrank pin engaging-the 'slot inthecrosshea'd,

and a pair of rigid vertical guides for the crossheadlocated on4opposite sides ofthe motor shaft; substantially `"as described.

2. A cloth fcttin'g machine having reciprocatin'g knife and a closelyembracing sheath therefor, in combination 'with driving and guidingmeans for the knife comprising a driving rod connected at its-lower endto the knife, a crossliead rigidly secured tothe upper end of the rodland having a Itransverse slot to receive a crank pin, va rotary drivingmotor, a crank connected with'v the Vshaft of the 4motor vand providedwith a crank pin engaging the slotin `the crosshead, a Apair of rigidvertical gu'idesfor the crosshead 4located on vopposite sidesof themotor shaft, anda-supplemental `guide for the driving rod^lo`catedbetween the crossliead and the point Where the rod is attached to theknife.

3. A cloth cutting-machine having -a--re- `ciprocating 'knife --and ay'closely-embracing sheath therefor, in combination with driving andguiding meansfo'r thel knife-comprising a "driving rod connected at itsIlower endfto 'the knife, a crosshead rigidlysecured tto' the 'uppery'end y-of the 'rod and 'having a=trans verse slot to receive acrankpin, rigid ver- `tical guides for the crosshead, a A'rotary*drivying motor, and Aa ycrank connected with the shaft of *the VArnotorand provided rwith a crank ,pin engaging Vfthe Vvslot lin the fcrosshead,

ytogether with a supplemental-guide for vthe driving rod 'locatedbetween -the cro'sshead -a-nd 'the point where the rod isl attached "to'the knife, the vertical guides and the supp-le- ?mental guide being `sopositioned that lines ljoining their centers form atriangleysubstantiallyas described. l

"ln testimony whereof, we'aix our signatures.

nYMAnMAtMrN. WILLIAM J.--Mansnanr..

Copies of this patent may 4be obtained for ve cents each, lay-addressingthe Commissioner of: Patents, "Washingtain,v il. U.

